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"Bent"
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جنوبي جزيرة العرب : رحلات في البحرين وجنوبي اليمن وعمان وشرقي السودان وسقطري
كتاب \"جنوبي جزيرة العرب\" كان الأول من نوعه الذي يقدم صورة حية حول الحكومة، والمناظر الرائعة، والعمارة، والحياة الاجتماعية، والأزياء، والعادات، والطب الشعبي والعديد من نواحي الحياة الأخرى في حضرموت، وفي نهاية عام 1896 أمضى الزوجان بنت شهرين في جزيرة سقطرى يدرسان حضارة لا تقل تفردا عن أية حضارة أخرى رأياها من قبل. وهذه الجزيرة كانت خليطا عجيبا من الشعوب والعادات الأمهرية والعربية والإفريقية، ثم فجعت مايبل بوفاة زوجها بعد أيام من عودتهما إلى بريطانيا، مما اضطرها إلى أن تقوم بتدوين أخبار الرحلة بنفسها في هذا الكتاب الثمين.
Book
Blood in the Borderlands
The Bents might be the most famous family in the history of the American West. From the 1820s to 1920 they participated in many of the major events that shaped the Rocky Mountains and Southern Plains. They trapped beaver, navigated the Santa Fe Trail, intermarried with powerful Indian tribes, governed territories, became Indian agents, fought against the U.S. government, acquired land grants, and created historical narratives. The Bent family's financial and political success through the mid-nineteenth century derived from the marriages of Bent men to women of influential borderland families-New Mexican and Southern Cheyenne. When mineral discoveries, the Civil War, and railroad construction led to territorial expansions that threatened to overwhelm the West's oldest inhabitants and their relatives, the Bents took up education, diplomacy, violence, entrepreneurialism, and the writing of history to maintain their status and influence. In Blood in the Borderlands David C. Beyreis provides an in-depth portrait of how the Bent family creatively adapted in the face of difficult circumstances. He incorporates new material about the women in the family and the \"forgotten\" Bents and shows how indigenous power shaped the family's business and political strategies as the family adjusted to American expansion and settler colonist ideologies. The Bent family history is a remarkable story of intercultural cooperation, horrific violence, and pragmatic adaptability in the face of expanding American power.
eBook
Circularly polarized luminescence in chiral orientationally ordered soft matter systems
Circularly polarized luminescent (CPL) materials have received significant attention in the field of fundamental science recently. These materials offer substantial advancement of technological applications, such as optical data storage, displays, and quantum communication. Various strategies have been proposed in self‐assembled materials consisting of inorganic, organic, and hybrid systems, particularly in the chiral orientationally ordered soft matter systems (e.g., chiral liquid crystals (LCs) and LC polymers). However, developing scientific approaches to achieve the pronounced and steerable circularly polarized light emission remains challenging. Herein, we present a comprehensive review on the recent development of CPL materials based on chiral LCs, including thermotropic LCs (cholesteric LCs and bent‐core LCs), lyotropic LCs (nanocellulose LCs and polyacetylene‐based LCs), and LC polymers (cholesteric LC‐based polymers, helical nanofibers, and helical network). In addition, the fundamental mechanisms, design principles, and potential applications based on these chiral LCs and LC polymers in soft matter systems are systematically reviewed. This review summarizes with a prospect on the latent challenges, which can strengthen our understanding of the basic principles of CPL in chiral orientationally ordered soft matter systems and provide a new insight into the progress in several fields, such as chemistry, materials science, optics, electronics, and biology. Representative chiral liquid crystals (LCs) with characteristics of circularly polarized luminescence, including cholesteric LCs, bent‐core LCs, lyotropic LCs, and LC polymers.
Journal Article
Derivatives of bent functions in connection with the bent sum decomposition problem
In this paper, we investigate when a balanced function can be a derivative of a bent function. We prove that every nonconstant affine function in an even number of variables
n
is a derivative of
(
2
n
-
1
-
1
)
∣
B
n
-
2
∣
2
bent functions, where
B
n
is the set of all bent functions in
n
variables. Based on this result, we propose a new iterative lower bound for the number of bent functions. We study the property of balanced functions that depend linearly on at least one of their variables to be derivatives of bent functions. We show the connection between this property and the “bent sum decomposition problem”. We use this connection to prove that if a balanced quadratic Boolean function is a derivative of a Boolean function, then this function is a derivative of a bent function.
Journal Article
Bent partitions
Spread and partial spread constructions are the most powerful bent function constructions. A large variety of bent functions from a 2m-dimensional vector space V2m(p) over Fp into Fp can be generated, which are constant on the sets of a partition of V2m(p) obtained with the subspaces of the (partial) spread. Moreover, from spreads one obtains not only bent functions between elementary abelian groups, but bent functions from V2m(p) to B, where B can be any abelian group of order pk , k≤m . As recently shown (Meidl, Pirsic 2021), partitions from spreads are not the only partitions of V2m(2) , with these remarkable properties. In this article we present first such partitions—other than (partial) spreads—which we call bent partitions, for V2m(p) , p odd. We investigate general properties of bent partitions, like number and cardinality of the subsets of the partition. We show that with bent partitions we can construct bent functions from V2m(p) into a cyclic group Zpk . With these results, we obtain the first constructions of bent functions from V2m(p) into Zpk , p odd, which provably do not come from (partial) spreads.
Journal Article
Spinopelvic pathways to bipedality: why no hominids ever relied on a bent-hip–bent-knee gait
Until recently, the last common ancestor of African apes and humans was presumed to resemble living chimpanzees and bonobos. This was frequently extended to their locomotor pattern leading to the presumption that knuckle-walking was a likely ancestral pattern, requiring bipedality to have emerged as a modification of their bent-hip-bent-knee gait used during erect walking. Research on the development and anatomy of the vertebral column, coupled with new revelations from the fossil record (in particular, Ardipithecus ramidus), now demonstrate that these presumptions have been in error. Reassessment of the potential pathway to early hominid bipedality now reveals an entirely novel sequence of likely morphological events leading to the emergence of upright walking.
Journal Article
New results on vectorial dual-bent functions and partial difference sets
Bent functions
f
:
V
n
→
F
p
play an important role in constructing partial difference sets, where
V
n
denotes an
n
-dimensional vector space over
F
p
,
p
is an odd prime. In [
2
,
3
], the so-called vectorial dual-bent functions are considered to construct partial difference sets. In [
2
], Çeşmelioğlu
et al.
showed that for certain vectorial dual-bent functions
F
:
V
n
→
V
s
, the preimage set of 0 for
F
forms a partial difference set. In [
3
], Çeşmelioğlu
et al.
showed that for a class of Maiorana-McFarland vectorial dual-bent functions
F
:
V
n
→
F
p
s
, the preimage set of the squares (non-squares) in
F
p
s
∗
for
F
forms a partial difference set. In this paper, we further study vectorial dual-bent functions and partial difference sets. We prove that for certain vectorial dual-bent functions
F
:
V
n
→
F
p
s
, the preimage set of the squares (non-squares) in
F
p
s
∗
for
F
and the preimage set of any coset of some subgroup of
F
p
s
∗
for
F
form partial difference sets. Furthermore, explicit constructions of partial difference sets are yielded from some (non-)quadratic vectorial dual-bent functions. In this paper, we illustrate that many results of using weakly regular
p
-ary bent functions to construct partial difference sets are special cases of our results. In [
2
], the authors considered weakly regular
p
-ary bent functions
f
with
f
(
0
)
=
0
. They showed that if such a function
f
is an
l
-form with
g
c
d
(
l
-
1
,
p
-
1
)
=
1
for some integer
1
≤
l
≤
p
-
1
, then
f
is vectorial dual-bent. We prove that the converse also holds, which answers one open problem proposed in [
3
].
Journal Article